In order to make possible an optimal feeling of comfort for a vehicle passenger, present-day vehicles are often equipped with an air-conditioning system. The function of the air-conditioning system is to provide, regardless of the weather or any waste heat, a passenger compartment atmosphere that is desired by the vehicle passenger. When an air-conditioning system of this kind is operated, however, devices within the air-conditioning system, in particular a fan of the air-conditioning system, which conveys air in the air-conditioning system, give rise to acoustic noise. This acoustic noise can be heard especially intensely when a vehicle motor is at a standstill. Because, in addition, vehicle drives are becoming increasingly quieter, the acoustic noise is becoming ever more strongly perceivable by a vehicle passenger, because noises due to the vehicle drive or other noises are not superimposed on this acoustic noise. Accordingly, the acoustic noise of the air-conditioning system is increasingly becoming an interfering noise for multimedia devices, for example, that are utilized in the vehicle.
Known from the document DE 10 2012 212 843 A1 is an air-conditioning unit, wherein the air-conditioning unit comprises a device for noise reduction, which has an analysis unit and a control unit and which produces sound waves that, through destructive interference, are designed to dampen the sound waves emitted by a fan of the air-conditioning unit.
Known in the prior art are regulating or control devices for air-conditioning systems that are designed to reduce an acoustic noise or an interfering noise of the air-conditioning system. In this case, a reduction in the acoustic noise or in the interfering noise occurs primarily via a reduction in a sound pressure level of the acoustic noise/interfering noise of the air-conditioning system. A sound pressure level is a logarithmic variable describing a magnitude of a sound event. The sound pressure level has been reduced up to now, for example, by using porous absorbers to reduce or to absorb high-frequency spectral components of a frequency spectrum of the noise. However, porous absorbers have the drawback that both the manufacturing materials and the underlying manufacturing technologies are very cost-intensive. The porous absorbers are also subject to physical limits in terms of their efficiency. Furthermore, it is known how to achieve the sound pressure level through a reduction in a low-frequency and medium-frequency spectral component of the frequency spectrum of the sound via active systems (“active noise cancelling”) or by destructive superimposition. However, it is disadvantageous here that, with a great application effort, high hardware costs and package problems must be anticipated.